Added an option (-i) to have dump_syms output header information only.

It is often helpful to check if a particular symbol file dumped by
dump_syms actually matches a version of a binary file we have. The
symbol output contains an ID which can be used to see if it matches
the binary file. Unfortunately, this ID is internally calculated
and not a standard hash of the binary file. Being able to output the
header information only will allow users to determine whether their
symbol file is up to date or not.

R=jochen@chromium.org
BUG=561447

Review URL: https://codereview.chromium.org/1864823002 .

Patch from David Yen <dyen@chromium.org>.

1 files changed, 19 insertions, 9 deletions

diff --git a/src/tools/linux/dump_syms/dump_syms.cc b/src/tools/linux/dump_syms/dump_syms.cc
index c51ae8cd..84953172 100644
--- a/src/tools/linux/dump_syms/dump_syms.cc
+++ b/src/tools/linux/dump_syms/dump_syms.cc
@@ -39,11 +39,13 @@
 #include "common/linux/dump_symbols.h"
 
 using google_breakpad::WriteSymbolFile;
+using google_breakpad::WriteSymbolFileHeader;
 
 int usage(const char* self) {
   fprintf(stderr, "Usage: %s [OPTION] <binary-with-debugging-info> "
           "[directories-for-debug-file]\n\n", self);
   fprintf(stderr, "Options:\n");
+  fprintf(stderr, "  -i:   Output module header information only.\n");
   fprintf(stderr, "  -c    Do not generate CFI section\n");
   fprintf(stderr, "  -r    Do not handle inter-compilation unit references\n");
   fprintf(stderr, "  -v    Print all warnings to stderr\n");
@@ -53,27 +55,29 @@ int usage(const char* self) {
 int main(int argc, char **argv) {
   if (argc < 2)
     return usage(argv[0]);
-
+  bool header_only = false;
   bool cfi = true;
   bool handle_inter_cu_refs = true;
   bool log_to_stderr = false;
   int arg_index = 1;
   while (arg_index < argc && strlen(argv[arg_index]) > 0 &&
          argv[arg_index][0] == '-') {
-    if (strcmp("-c", argv[arg_index]) == 0) {
+    if (strcmp("-i", argv[arg_index]) == 0) {
+      header_only = true;
+    } else if (strcmp("-c", argv[arg_index]) == 0) {
       cfi = false;
     } else if (strcmp("-r", argv[arg_index]) == 0) {
       handle_inter_cu_refs = false;
     } else if (strcmp("-v", argv[arg_index]) == 0) {
       log_to_stderr = true;
     } else {
+      printf("2.4 %s\n", argv[arg_index]);
       return usage(argv[0]);
     }
     ++arg_index;
   }
   if (arg_index == argc)
     return usage(argv[0]);
-
   // Save stderr so it can be used below.
   FILE* saved_stderr = fdopen(dup(fileno(stderr)), "w");
   if (!log_to_stderr) {
@@ -82,7 +86,6 @@ int main(int argc, char **argv) {
       // Add this brace section to silence gcc warnings.
     }
   }
-
   const char* binary;
   std::vector<string> debug_dirs;
   binary = argv[arg_index];
@@ -92,11 +95,18 @@ int main(int argc, char **argv) {
     debug_dirs.push_back(argv[debug_dir_index]);
   }
 
-  SymbolData symbol_data = cfi ? ALL_SYMBOL_DATA : NO_CFI;
-  google_breakpad::DumpOptions options(symbol_data, handle_inter_cu_refs);
-  if (!WriteSymbolFile(binary, debug_dirs, options, std::cout)) {
-    fprintf(saved_stderr, "Failed to write symbol file.\n");
-    return 1;
+  if (header_only) {
+    if (!WriteSymbolFileHeader(binary, std::cout)) {
+      fprintf(saved_stderr, "Failed to process file.\n");
+      return 1;
+    }
+  } else {
+    SymbolData symbol_data = cfi ? ALL_SYMBOL_DATA : NO_CFI;
+    google_breakpad::DumpOptions options(symbol_data, handle_inter_cu_refs);
+    if (!WriteSymbolFile(binary, debug_dirs, options, std::cout)) {
+      fprintf(saved_stderr, "Failed to write symbol file.\n");
+      return 1;
+    }
   }
 
   return 0;